This invention concerns an apparatus for injecting a liquid into the vascular paths of a lignified plant.
Through direct injection into the stem of plants, in particular trees, growth regulators and protective agents are directly conveyed to trees. An important area of application of this technique of injection is also the prevention of disease or the combating of insects, which nourish themselves on foliage or on wood grains. Insects can be combated just as are virus and fungus infections by means of this type of chemotherapy by the application of antibiotics and/or systematic conveyance of insecticides. It is known that the combating of various insect epidemics, such as the psendophilus testacens in Ghana in March 1978, was successful in this way. Also, the spread of diseases can be brought under control.
In practice, the applied liquids were conveyed to the plants by gravity through discharge pipes of a container. Such apparatuses are not intended for poisonous substances, however, because the containers cannot be tightly closed. Highly effective modern insecticides are poisonous to humans and must be kept in completely closed containers.
Insecticides with a phosphorous base are sufficiently effective that only quantities of 3 to 6 cm.sup.3 must be conveyed. Such substances are, however, poisonous to such an extent that instructions for their handling must be strictly followed.
DE-C 12 77 618 proposes to form the container out of two feather-shaped parts with closing bottoms able to conversely slide into each other, with their surface shells tightly superimposed on each other, to thereby solve the problem of tight containers. The liquid then flows by gravity out of the container into the trunk of the tree.
Another solution involves a container in which an additional space for the production of a compressed gas is provided--see DE-C 12 40 325.
However, for the application of the medium, an injection needle must first be inserted into the trunk up to those depths in which the vascular parts of the plants are found. In DE-C 15 82 802 an impact apparatus is utilized to drive the injection needle into the trunk, in order to then be able to apply a container such as described above. Instead of driving an injection needle, DE-A 28 35 430 proposes to first drill holes in the trunk and then insert the nozzles into these holes.
In all of these known arrangements an injection needle or a nozzle is first inserted into the stem of the plant to be treated, and then the liquid in a desired quantity is introduced through the needle or the nozzle.
Up to now only one apparatus is known with which a liquid can be conveyed simultaneously with the formation of an access to the vascular parts--see U.S. Pat. No. 2,853,833. A cylindrical space with a valve is provided in an axe body, is opened through a strike with the axe by a tappet. A liquid is thereby conveyed, and departs through several canals near the cutting edge of the axe body. This is disadvantageous, however, because the plant is severely injured.